(1) Field of the Invention
The present invention relates to a centrifugal separator type paint mist containing gas cleaning apparatus to be installed in e.g. a painting booth, and more particularly to a cleaning apparatus of the above-noted type comprising a concave guide face extending downwardly from a downstream side end of a cleaning liquid flow-down face in a flowing down direction of cleaning liquid, the concave guide face being formed as a curved arcate face, a discharge guide face disposed at a downstream side end of the concave guide face for laterally discharging the cleaning liquid, a gas orienting face for orienting a paint mist containing gas fed from the upperside towards the concave guide face, whereby the paint mist containing gas is discharged through a discharge opening formed between a downstream side end of the gas orienting face and a portion of the concave guide face most adjacent the downstream side end of the gas orienting face, the discharge opening having a width smaller than an average radius of the concave guide face, the paint mist containing gas being discharged in a direction substantially along a tangential line of the concave guide face.
(2) Description of the Prior Art
As for the conventional paint mist containing gas cleaning apparatus, in addition to the above-described centrifugal separator type (see FIG. 7), there are also known other types as shown in FIGS. 8 through 10.
FIG. 8 shows a so-called target type, in which paint mist containing gas A and flowing-down cleaning liquid W are caused to strike at a high speed against a target plate 01 trapping the paint mist contained in the gas trapped into the cleaning liquid W (BP 2,110,952 Official Gazette). FIG. 9 shows an angularly curved flow passage type. In the case of this type, the paint mist containing gas A is caused to flow through an angularly curved flow passage 02 in which the paint mist is separated by inertia from the gas and trapped into the flowing down cleaning liquid W (BP 2,110,952 Official Gazette). FIG. 10 shows a vortex flow type. In the case of this type, the paint mist containing gas A and the flowing down cleaning liquid W are caused to flow at a high speed through a flow passage having a pair of curved flow passages 03 and 04 laterally symmetrical to each other and a constricted discharge opening 05 having a small diameter, during which one portion of the gas-liquid mixture guided by the left side curved flow passage 03 and the other portion of the gas-liquid mixture guided by the right side curved flow passage 04 are caused to collide with each other at a vortex flow chamber 06 while flowing in the form of vortex streams because of the effect of the respective curved flow passages, whereby the paint mist is trapped into the cleaning liquid W.
Aside from the above apparatus, there are also known other types of mist-containing gas cleaning apparatuses (e.g. U.S. Pat. No. 4,350,506, U.S. Pat. No. 4,257,784, USSR 628,379, Japanese published patent 55-6427).
In comparison with the above-described target type or the vortex flow type, the centrifugal type, to which the present invention relates, has the following advantages. First, there occurs less pressure loss. Second, there occurs less adhesive accumulation of the paint. Third, there is wasted less energy because of the less pressure loss. Fourth, there occurs less operating noise. Last, because of the less adhesive accumulation of the paint, even with less frequent maintenance operations, the apparatus may maintain a high paint mist collecting efficiency for a long period of time.
Further in comparison with the angularly curved flow passage type having only the angularly curved flow passage, the centrifugal separator type is advantageous in its much higher paint mist collecting efficiency.
Conventionally, the centrifugal separator type paint mist containing gas cleaning apparatus having the above-noted advantages is constructed as shown in FIG. 7 (BP 2,110,962). In this conventional apparatus, a discharge opening 1E formed between a downstream side end P of a gas orienting face 1D and a portion Q of a concave guide face 1B most adjecent the downstream side end P of the gas orienting face 1D is disposed in such a way that a tangential line l of a concave guide face 1B is formed substantially along the horizontal line or formed with an extremely small slope relative to the horizontal line.
Incidentally, in this FIG. 7, a reference mark 1A denotes a cleaning liquid flowing-down face extending continuously from an upstream side end of the concave guide face 1B, a mark 1C denotes a discharge guide face for laterally discharging the cleaning liquid W, a mark d denotes a width of the discharge opening 1E and a reference mark R denotes a radius of the arcuate concave guide face 1B, and denotes a discharge direction of paint-mist containing air A.
With all the above-described advantages over the other conventional apparatuses, the above conventional centrifugal separator type paint mist containing gas cleaning apparatus still need be improved in that there is still a tendency of the adhesive accumulation of the excess paint, though less conspicuous than the other types, at a portion of the concave guide face adjacent the discharge opening.